Determining the Antiquity of Dog Origins: Canine domestication as a model for the consilience between molecular genetics and archaeology, by MICHELLE J RAISOR
BAR International Series 1367. 2005. 96 pages, 25 figures, 6 tables. ISBN 1 84171 809 2 (£30.00)
The note, ‘About the Author’ at the front of this publication describes
Michelle Raisor as a person of many and varied accomplishments. Besides a B.Sc
in recreation and parks from Texas A & M University, she has an MA in
Anthropology, and she has worked as a research associate in a number of
different molecular genetics laboratories. Raisor was also a research associate
in a department of veterinary medicine, and she has a life-long passion for
dogs, so she is well qualified to enter the fray on where, when, and from what
was the dog first domesticated.
There are six sections to Determining the Antiquity of Dog Origins, a
long chapter on the basics of molecular genetics follows a short introduction.
This is followed by a chapter on the behaviour of wolves, followed by another
long chapter on the archaeological record, which is mainly concerned with the
fossil and subfossil remains of canids. This is followed by a discussion and
conclusion.
The collaboration, or what Raisor calls ‘consilience’, between molecular
geneticists and archaeologists and archaeozoologists has only proliferated
relatively recently and it gives me a great feeling of déjà vu for the
beginnings of radiocarbon dating, which in the 1950s and 60s grew from what
seems to me to be very much the same sort of collaboration, but between
physicists and archaeologists. What is so similar about molecular genetics and
radiocarbon dating when applied to archaeology is that the researchers on each
side know so little about the science of the other, and so each has to take
what the other says on trust. This has led to the publication of some
extraordinary errors, for example in the dating of the dog remains from Jaguar
Cave in Idaho that were first dated to c. 10,370 BP (making them the acclaimed,
earliest dogs in North America), but later the bones were directly dated to c.
3200±80 BP and 940±80 BP. And in mtDNA analysis, the best known recent example
is the misinterpretation of the molecular evidence published by Vilà et al. in
their Science paper of 1997, in which they stated that the split between the
wolf and the dog occurred c. 135,000 years ago. It is now considered
that Vilà et al., in arriving at this date, did not take into due
account the probable errors in their estimates, particularly in the calibration
point between the outgroup and the wild ancestor, ie the one million years that
was taken as the time of split of an ancestral canid into the separate species
of coyote and wolf (see Dobney & Larson, in press).
Molecular geneticists and archaeozoologists are beginning to appreciate much
the same sort of difficulties about each other’s research as radiocarbon
physicists and archaeologists did some forty years ago. They realize that great
caution needs to be placed on the interpretation of evidence from both sides,
but it seems that Michelle Raisor has no qualms about entering both fields and
publishing her views and interpretation of mitochondrial inheritance, mapping
the canine genome, evolution, the process of domestication, behavioural
patterns of wolves and dogs, osteological differences between wolves and dogs,
and lists of the worldwide sites from where early dog remains have been
recovered. In many ways this makes her book a useful review of the present
status of evidence on the origins and antiquity of the domestic dog and it has
a commendable bibliography, but regretfully no index. However, Raisor has a
bias in her thinking about the evolution of the domestic dog that I have
commonly heard from dog breeders, but never from biologists, and that is that
the wolf could not be the direct progenitor of the dog because there are too
many differences in their behaviour.
I am an archaeozoologist and I have no more knowledge of the technology of
genetics than I have of radiocarbon dating, so I am not qualified to comment on
Raisor’s description of the ‘Basics of molecular genetics’, but I wonder
whether she gave this section to a geneticist for review before submitting it
for publication? There are no acknowledgements in the book and regretfully it
is clear that the text received no copyediting, for there are many typos and
errors of grammar and style.
Raisor goes wrong in arguing at length against various theories about the
domestication process, which as far as I know, no scientist has ever put
forward, such as, ‘what would the advantage be for early man to bring a
dangerous carnivore into its camp and condition it to have no fear of humans?’
And again, no archaeozoologist would admit to holding the simplistic view that,
as early as 15,000-135,000 years ago, humans would or could have intentionally
captured, tamed or controlled wild wolves, and then selectively bred them to
produce dogs. Raisor states that it is because of her disbelief in this theory
that she supports an alternative hypothesis of canine domestication. Although
her reasoning is difficult to follow, it seems she ends up with a theory for
the process of domestication of the dog, which does not differ widely from that
of mainstream archaeozoology. Raisor first accepts that the changes in the
mtDNA between wolves and dogs that were recorded by Vilà et al. could
indicate that a separation occurred 135,000 years ago, but she suggests these
changes were a result of natural evolution in a changing environment and had
nothing to do with human intervention (p. 84). On p. 86 it transpires that she
sees this changed environment not as the natural world but as the surroundings
of human camps where the canids that were transitional between wolves and dogs
scavenged. Then, ‘at approximately 15,000 years ago, some dogs had sufficiently
evolved that some especially adaptive animals could be assimilated into human
culture.’ This seems to me to be a reasonable hypothesis, except that its early
beginnings at 135,000 years ago are now discounted, and she doesn’t mention the
salient point that in order for changes in the genetic constitution of an
organism to be inherited, and thereby to evolve into a new form, there has to
be reproductive isolation from its ancestral population.
In this review, Michelle Raisor has shown herself to be a pioneer in
consilience (defined in the Oxford Dictionary as ‘jumping together’), between
molecular genetics and archaeozoology. Clearly, reviews of this kind will be of
great value for the future of both disciplines, but it is essential that they
should be written by a scientist with a real understanding of the strengths and
weaknesses of the methodology together with an archaeozoologist who can
critically assess the results, rather than taking them at face value and then
constructing hypotheses to fit them. It is also essential that both sides
should be expertly refereed before agreement on publication is reached.
Juliet Clutton-Brock
Editor, Journal of Zoology
References
Dobney, K & Larson, G. in press. Genetics and animal domestication: new
windows on an elusive process. Journal of Zoology , (2006)
Vilà, C., Savolainen, P., Maldonado, J. E., Amorim, I. R., Rice, J. E.,
Honeycutt, R. L., Crandall, K. E., Lundeberg, J., & Wayne, R. K. 1997.
Multiple and ancient origins of the dog. Science , 276, 13 June,
1687-1689
Review Submitted: September 2005
The views expressed in
this review are not necessarily those of the Society or the Reviews
Editor.
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